Apparatus for utilizing furnace gases in the reclaiming of bone black and like materials



ERIALS 4 Sheets-Sheet 1 1936- N. R. ANDREWS APPARATUS FOR UTILIZING FURNACE GASES IN THE RECLAIMING OF BONE BLACK AND LIKE MAT Original Filed April 24, 1933 wan/7mm 0 .1: 12

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I'BOKEC CHER F/LTE'K.

INVENTOR N HANIEL R Dec. 22, 1936. N R ANDREWS 2 ,064,813

APPARATUS FOR. U'TIL'IZING FURNACE GASES IN THE RECLAIMING OF BONE BLACK AND LIKE MATERIALS Original Filed April 24, 19.33 4 Sheets-Sheet 2 INVENTOR Dec. 22, 1936. N R ANDREWS 2,064,813

APPARATUS FOR UTILIZING FURNACE GASES IN THE 'RECLAIMING OF BONE BLACK AND LIKE MATERIALS Original Filed April 24, 1933 4 Sheets-Sheet 3 N. R. ANDREWS UTILI Dec. 22, 1936. 2,064,813

APPARATUS FOR ZING FURNACE GASES IN THE RECLAIMING OF BONE BLACK AND LIKE MATERIALS Original Filed April 24, 1933 4 Sheets-Sheet 4 fiieZR./7ndrews C, WW

.Mztim Patented Dec. 22, 1936 UNITED STATES PATENT OFFICE GASES IN THE RECLAIMING OF BONE BLACK AND LIKE MATERIALS Nathaniel R. Andrews, Yonkers, N. Y.

Original application April 24, 1933, Serial No. 667,723. Divided and this application April 24,

1933, Serial No. 667,722

8 Claims.

This invention relates to new and improved apparatus for reclaiming or reconditioning boneblack or animal charcoal, commonly known in the sugar refining and. allied arts as char.

The present application is a division of my copending application, Serial No. 667,723, filed April 24, 1933, now Patent No. 1,971,895. My acknowledged patent is drawn to a process of reclaiming bone black from spent char while the present application is drawn to one type of apparatus which can be employed in the process of the said patent.

One of the objects of the invention is to provide new and improved apparatus such that the revivifying or reconditioning of the char is accomplished more economically than it has been possible to process the char in apparatus as hitherto constructed. I

Another object of the invention is to provide new and improved apparatus for processing char whereby. gases from the boiler furnace of a sugar refining plant may be most economically and efficiently utilized in the reconditioning or revivifying of the char.

Another object of the invention is to provide new and improved apparatus wherein the vapors and products of combustion driven off or distilled off from the char during the process of reconditioning the latter may be effectively utilized in preheating the boiler water.

Another object of the invention is to provide new and improved apparatus whereby air utilized in cooling the reconditioned or revivified char and thus heated by the heat given off in cooling ltahe char may be utilized in the furnace of the oiler.

Another object of the invention is to provide new and improved apparatus of the above character wherein the danger of destroying or injuring the char structure during the revivifying or reconditioning process is entirely eliminated. Another object of 'the invention is to provide apparatus of the above character wherein boiler new and improved apparatus of the above char-.

acter wherein boiler furnace gases are utilized in the reconditioning of char such that lower temperatured furnace gases may be mixed with higher temperatured furnace gases so that the re.-

sultant mixture will be at the maximum temperture required for processing char. Y

Another object of the invention is to provide new and improved apparatus of the above character wherein a blanketing or extinguisher action is provided for the char in process in the event that the temperature thereof rises to such a point that the char structure might be'injured or destroyed.

Another object of the invention is to provide in apparatus of the class described, means whereby the rate of processing the char by the heat of the boiler furnace gas is such that said rate of processing or the amount of char processed is determined by the rate of fuel burned in the boiler furnace, or is proportional to the steam demand upon the boiler and therefore to the rate of processing of the sugar.

More particularly,'my new and improved apparatus for reconditioning or reclaiming char contemplates the use of the boiler furnace gases of a sugar refinery in such a way that the heat produced by burning off or distilling off the im purities or foreign matter in the char being processed is utilized for preheating the boiler water, the air used for cooling the processed char and thus heated is used in the combustion chamber. of the boiler furnace so that the apparatus becomes, in efiect, an economizer for the boiler breathing" with the boiler, so that the heat reclaimed from the furnace gases and also the heat produced by combustion of the impurities or foreign matter in the char is proportional to the rate of fuel burning in the boiler furnace.

It is, of course, well known that the steam generated in a sugar refinery is employed almost exclusively in the processing of the sugar; for example, inthe evaporating pans, etc. Any steam used for heating of the building orfor other nonsugar uses is usually exhaust steam from one or more of the sugar processing operations. It is therefore clear that, if the char processing is controlled in such manner as to be proportional to the steam demand or to the fuel consumed in the boiler room of a refinery, it is also substantiaily proportional to the rate of sugar processing, which in turn is proportional to the demand for the char employed during the processing. I have found that a control-based in this manner is convenient, effective, inexpensive and labor saving.

Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings wherein I have illustrated a preferred form of embodiment of my invention, some parts of the apparatus'being illustrated schematically, v

Figure 1 is a view partly in elevation and partly in section illustrating my improvedapparatus,

Figure 2 is a perspective view of the char processing part of the apparatus showing portions of the flues which lead to and from the boiler furnace, I

Figure 3 is a vertical sectional view of a. part of the reconditioning apparatus showing a detail of construction,- 4

Figure 4 is a horizontal sectional viewshowing schematically the disposition of the char feed tubes relative to the char processing tubes,

Figure 5 is a vertical sectional view, partly schematic, showing the means employed for automatically discharging char to be processed into the apparatus, while Figure 6 is a diagrammatic showing of the control features of my invention.

. Referring now to the drawings wherein similar reference characters refer to similar parts throughout the several views of the drawings, the reference numeral I denotes the charfilter having a hopper tube which is adapted to discharge the char to be processedupon a belt conveyor 3,

said belt conveyor discharging the char into the boot of the bucket elevator E. This bucket elevator discharges the char into the upper end of a feed hopper 5, having a chute 5 The reference numeral 6 denotes a screw conveyor which forms its own trough in the char and distributes the latter evenly in the feed hopper chute 5 any excess of char spilling into the chute through the pipe I. which delivers it into .the boot of the bucket elevator 4. The elevator This feed plate 8, which may be adjustable, is'

adapted to regulate the amount of char being delivered from the chute 5 onto an inclined tubesheet 9- v I The reference numerals Illa. b. c. designate what may be termed char feed tubes, said tubes.

having their upper ends expanded or otherwise fixed into apertures formed in the inclined tube sheet 9. The char flows downwardly through the feed tubes Illa. b. 0. into the process tubes I la. b.

c.. which process tubes have their upper ends expanded into or otherwise fixed in the tube sheet I2. The process tubes IIa. b. c. extend downwardly through a tube sheet I3, a baflie plate I4,

and the tube sheet I5.

The process tubes II a. b. c. are preferably expanded into or otherwise snugly fitted in apertures'provided in the tube sheets I3 and I5, and the baffle plate I 4. Y

. It will be noted by reference to Figures 3 and 4 of the drawings that the feed tubes Illa. b. c. are of larger diameter than the diameter of the process tubes Ila. b. c. and are out of vertical alignment therewith, in the present instance the structure being such that a single feed tube will serve four of the process'tubes. The tube sheet I2 is provided with a plurality of frustro-conical members I2 positioned thereon directly underneath each of the feed tubes as illustrated in Figure 3 of the drawings. The purpose of these members I2 is to direct the char to be reconditioned into the various process tubes as indicated in Figure 3 of the drawings.

The feed tubes as well as the process tubes, it will be noted, are disposed vertically and in parallel relation, the char falling by gravity through both sets of tubes.

The reference numeral I6 denotes what may be termed the char draw consisting of a stationary plate having slots or holes No. b. 0. provided thereon, and movable bars I8a. b. 0., only one of which is shown herein, raised upon the stationary plate I6. These bars Ilia. b. 0. have fixed thereon and at right angles thereto the bars I9a. b. 0.

' The movable bars I8a. b. c. are given a reciprocal motion by means of the char draw drive consisting of the connecting rod 20, connected to said movable bars and actuated by a crank pin 2I, provided, upon a disk 22, revolving about the center 23, said disk'being driven by any suitable means, such as a stoker mechanism, forming part of an automatic combustion control mechanism shown schematicallyat 22.

It will be seen that (Figure 1) the reciprocating motion given the bars Ifla. b. c. and consequently to the bars I9a. b. c., the char is pushed from side 'to side, causing it to flow intermittently through the slots I'Ia. b. 0. provided in the stationary plate I6.

These slots I Ia. b. c. in the plate I6 are so 10- cated with respect to the bars I9a. b. c. that when the latter are centrally disposed under the lower ends of the process tubes. Ila. b. 0., the angle of bars I9a.. b. 0., operated as above described, from the disk 22. In other words, the speed of rota-' tion of the disk 22 determines the amount of discharge of the char from the process tubes through the apertures of the plate I6.

The char after passing through the char draw falls into the hopper 23, from which it fiows onto the conveyor belt 24, which in turn mentalities referred to by the prefix number may be provided.

Figure 2 of the drawings shows the manner in 30, under the lower edge of the baflle 34, and then out of the boilerzinto the flue 35, or only aportion of the combustion gases may pass out of the boiler simultaneously at each of the above described routes.

The flue 36 connects the flues 33 and 35, and a damper 31 is provided in the flue 35, a damper 38 in the flue 33, and a check damper 39, provided with an arm or lever 40 and a weight 4|, closing against stop 42, is provided in the flue 36. Damper 39 is so counterbalanced that in free air or free gases it just closes against stop 42, but is free to swing downwardly thus connecting,

.under certain conditions,.flues 33 and 35.

The gases flow from flues 33 and 35 into the enclosure or heating chamber formed by the tube sheets I2 and I3, and the casing 43, passing upwardly around the process tubes Ila. b. c., and into the flue 44, thence through exhaust fan 45, and up the chimney or stack 46, to the atmosphere.

As already stated, the char comes from the char filters containing from fifteen to twenty percent of moisture. This moisture, of course, must be driven from the char before, the latter can be heated to such a temperature as will permit the burning or distillation of the solid impurities of the char.

It is also an important object of my invention to conserve as much of the heat energy of the boiler furnace gases as it is possible to do. This is accomplished by utilizing as fully as possible the furnace gases at their normal exit tempera ture-level, using only enough of the higher temperature furnace gases as is necessary properly to process the char. ,The char, of course, falls by gravity through the process tubes IIa. b. c., in accordance with the operation of the char draw.

I therefore provide the flue 35 so that furnace gases at their normal exit temperature level may be conducted'directly into the upper part of the heating chamber formed by the casing and the tube sheets I2 and I3. These gases conducted through the flue 35 are sufiiciently high in temperature to drive out all or the major part of the moisture and the more volatile constituents of the char before the latter has reached the higher temperature zone of the heating chamber to which the higher temperature gases are conducted by the flue 33.

The gases at their normal exit temperature level, are, therefore, discharged from the flnal pass into the heatingchamber at a location considerably above the point where the higher temperature gases enter said chamber.

Only enough of the furnace gases at their normal exit temperature level passes through the flue 35 and past the check damper 39 as is necessary to temper or cool the higher temperatured furnace gases so that the resultant mixture of the higher and lower temperature gases will be of a temperature sufficiently high to cause such combustion of the foreign matter in the char at the point where these higher temperatured gases enter as is necessary properly to processthe same after the moisture or a large part-stl'iereof has.

been driven from the char by the lower temperature gases entering the heating chamber through the flue '35.

Free air is drawn into the blower 41, and forced through the flue 48, into the closed pressure or discharge chamber 48*, the top wallof which is formed by the tube sheet I5. Air passes into the process tubes I Ia. b. 0. through the spaces between the particles of char at the lower end of the process tubes IIa. b. c. This air is preheated to some extent by being passed in heat transfer relationship with the reconditioned char in hopper 23.

The products of combustion formed by burning off materials subtracted from the sugar solution by the char distillates, and the steam driven from the char pass out from the upper end of the process tubes Ila. b. 0. into an enclosed vapor chamber, the top and bottom walls of which are formed by the tube sheets 9 and I2 respectively.

From this vapor chamber the steam and vapors from the process tubes Ha. I). c. mingle with some air which is drawn through the char in the feed tubes Ilia. b. 0., pass through the flue 49, into the surface condenser or heat exchanger 50, and thence into the flue 5|, into out through the pipe I5, and is trapped from the apparatus by means of the trap 16.

Free air passes into the flue 53, through the spaces provided between the process tubes Ila. b. 0. under the baffle plate I4, into the flue 54, and in reverse direction, directly over bafile I4, and the tube sheet I3, thence to flue 55, through the blower 55 into the air chamber 51, from whence it passes into the furnace 41 through the fuel bed 58. Thus the air utilized to cool the reconditioned char is preheated and discharged into the boiler furnace.

The boiler feed water entering through the pipe 59 flows through the surface condenser or heat exchanger 50, passes by way of pipe 60, into the boiler drum 6|. Thusthe heat generated by burning out the foreign matter present in the char is conserved by preheating the boiler water.

For purposes of this description of my improved apparatus, I assume that the boiler and the furnace are equipped with a combustion control, this term including an automatic stoker I03 which proportions the rate of fuel feed to the steam demands upon the boiler. Since automatic combustion control mechanisms are conventional I have illustrated the various elements in Fig. 6 diagrammatically. A steam meter I00 is shown, this meter being electrically connected to a stoker control unit IOI. This unit in turn is connected electrically to the motor I02 which drives the automatic stoker I03 through the eccentric disc H0. The steam meter I00 measures .the steam demand, i. e. steam flow and the automatic stoker I03 is driven by stoker control IOI at a speed proportional to this demand.

The stoker control IOI is shown electrically connected to motor 22', which drives the eccentric disc 23 at a speed proportional to the steam demand or to the speed of the stoker I03. The disc 23 reciprocates the char draw I8 and thus the feed of char past this point is automatically proportioned to the steam demand or the rate of the stoker I03. The blower 56 is likewise driven from the stoker control IOI in proportion to steam demand-pr rate of stoking by means of the electrical connections shown. This causes the air fed to the furnace to be proportioned to therate of stoking.

The blower 41 is likewise driven from the stoker control by the electrical connections shown in Fig. 6. This blower therefore automatically produces a pressure within the pressure chamber 48 anda flow of conditioning air through process tubes Ila. b. c. at a rate proportional to steam demand or rate of stoking. Since the conditioning air cools the char this is also accomplished at a rate proportional to steam demand or rate of stoking. Exhauster is likewise driven from s'toker control l9l at a rate proportional to steam demand.

It is also assumed that the elevator 4, and the conveyor 6, are driven continuously at a constant rate.

The belt conveyor 3, by means of which the char to be processed is-delivered into the boot'of the elevator 4, is driven by the motor 62, as shown, which is controlled as to stopping and starting by the swinging targets 63 and 64a. 2). 0., located in the feed hopper chute 5 Target 63 is located at the end of the feed hopper chute 5 furthest fromthe discharge of elevator Targets 6 2a. b. 0., only one of which is shown, extend along the lower portion of the feed chute 5 These targets normally hang by gravity invere tical positions, but, as indicated, are pushed aside by the char in the hopper and its chute. Each target is provided with the lever 65, and the armatures 66, which make electrical connections at the positions shown, these energizing coils which throw motor control contactors, not shown, in or out, thereby stopping or starting the motor 62, which drives the conveyor 3.

The construction is such that any one of the targets 6411. b. 0. may start the motor 62. That is to say, the strength of the starting coil energized by thetargets 64a. he is sufiicient to overcome the strength of the stopping coil controlled by the target 63 so that the motor 62 will start when any of the targets 68a. b. c. are vertical re-v gardless of the target 63.

From the foregoing, it' will be seen that this automatically operated mechanism insures that a uniform supply or constant head of char to be processed will, at all times, be maintained upon the surface of the tube sheet 9.

A thermostatic control consisting in part of a thermocouple, the hot junction of which is inserted in the char in one of the process tubes Ha. b. c. at the point 68, operates damper 38 to admit gas from the high temperature zone in a quantity or volume sufficient, when tempered or cooled with gas from the low temperature zone of the boiler furnace, to raise and maintain the temperature of the char in process tubes I la. b. c. to the desired degree. Thus, the thermocouple 68 is connected to temperature control )4 (Fig. 6) which in turn is electrically connected to motor III which operates to open damper 318 when the temperature at 68 has fallen below a given point.

A temperature control comprising a thermocouple having its hot junction inserted in flue 33 at 61 operatesto adjust damper 31 in flue 35 so that suficient gas will flow from flue 35 through flue 36, past counter-balanced check damper 39, into flue 33, to maintain the temperature of gas at the point 61 at a constant, desired temperature. Since the temperature f these gases is held constant at the point 61, it is the volume rather than the temperature of these gases which is controlled inorder to maintain the char at the point 68 at. a constant temperature. Any increased flow of gases through damper 38 is followed by a correspondingly increased flow past the check 39.

As shown in Fig. 6, thermocouple 61 is connected to the temperature controller I96 which in turn is electrically connected to motor 2 which operates to close damper 31 when the temperature at 61 has risen above a certain point.

The check damper 39 prevents any flow of gas from flue 33 to flue 35.

The damper 52 in the flue 99 is operated thermostatically from the point 69, by means of a thermocouple having its hot junction inserted in the char in one of the process tubes I la. b. c. in such a manner that if for any reason the char temperature in the process. tubes rises above a .certain fixed degree, the damper 52 will close and will not again open until the temperature of the,

- to escape through flue 49, their easiest course of travel will be downwardly through the process tubes thereby blanketing or extinguishing such combustion in the process tubes in the event that the temperature of the char has risen above a fixed point.

To prevent condensation of the steam and vapors at the entrance of charto the process tubes Ila. b. c., the feed tubes Illa. b. 0., the inclined tube sheet 9, and the sides of the vapor chamber directly underneath the tube sheet 9, are covered with heat insulating material. relative position of the feed tubes and the process tubes is made such that the char does not entirely fill the ends of the process tubes, as will be seen by reference to Figure 1 of the drawings. the vapor chamber through the char in the feed tubes, very little of the incoming char is exposed to the steam rising from the process tubes.

It will, therefore, be seen that I have provided an apparatus for revivifying or reconditioning char well adapted to attain, among others, allthe ends and objects above pointed out in a. very simple manner.

By the zoning of the gases in the passages of the boiler furnace, thus providing a bleeder" type furnace and delivering, that is to say, by using gases at one or more temperature levels, one of which may be the normal exit gas temperature and the other or others at successively higher temperature levels, I am able by mixing of the lower temperature gas with the gas of higher temperature to gain and maintain a de- Moreover, the- Also, since some air is allowed to enter' sired temperature somewhere between the two or I more temperatures without regard (within certain limits, of course) to the amount of gas required at the said desired temperature for processing.

It will also be seen that I am able to air employed in the cooling of the char; in the combustion furnace of the boiler and I am also able to use the heat in the steam and vapors,

driven from the char in the processing tubes to heat the boiler feed water. I am also able to control the combustion of th use the char.

tubes, and am also able so to regulate the char feeding equipment whereby condensation, which would tend to bridge the char and thus prevent its free entry into the process tubes, is avoided.

Another advantage of my improved apparatus is that the char is treated in vertical, stationary tubes of comparatively small diameters in such a manner that the char entering each tube is dried, burned andcooled in said tube which is continuous from end to end, the char being exposed to such oxidizing agent, air'or gas in the tube as is admitted at the lower end and moved upwardly through the tube this air supply being automatically proportioned to the amount of char being processed.

Another and most important end obtained by means of my improved apparatus is the manner of controlling the amount of char being processed, or the rate of flow of char into the process tubes as well as the amount of air admitted, from the rate of fuel burned in the boiler furnace so that the char processing apparatus breathes with the boiler or is proportional to the steam demand upon the boiler or to the fuel consumed whereby the heating of the feed water and the preheating of the air entering the boiler furnace makes this process a true fuel economizer complete in itself for the boiler.

There is a complete combination or cooperation between the boiler furnace and the char processing equipment. As stated previously the steam demand or rate of fuel consumed by the boiler of a refinery is roughly proportionalto the rate of sugar processing and hence to the demand for As the sugar processing increases more steam is used in the evaporating pans etc., this produces (through the boiler combustion control mechanism) an automatic increase in the fuel consumed in the boiler; i. e. the automatic stoking mechanismspeeds up. More air is required" for the furnace and this is supplied automatically by the control attached to blower 56. The control disk 22 operating the char draw automatically speeds up, delivering more reconditioned char. There is a demand for additional flue gases to heat up the process tubes more rapidly and this increase is producedfautomatically by the increased feed of fuel/and air to the boiler furnace. There is also a" demand for more conditioning air to pass upwardly through the processing tubes. This is supplied by the increased pressure produced in the char discharge chamber by the automatic speeding up of blower 41. There is also an increased demand for the preheating of the boiler feed water and this is supplied by the additional vapors rising through the process tubes which deliver their heat to the boiler feed water in the feed heater 50. Each element of the equipment therefore depends upon the operation of the remaining elements.

As has already been stated, certain parts of the apparatus are illustrated in the drawings schematically. ,7

The construction of the parts or elements shown schematically is a matter of ordinary mefeed stoker, and a system of bafliing is. provided designed to attain the ends sought in the present invention. In this apparatus, of course, any type of boiler and fuel burning equipment may be employed so long as the zoning and control of the gases of combustion and the adaption of the char reclaiming apparatus as a heat reclaiming system is associated with the boiler.

Although not illustrated in the drawings, it will be noted that such parts of the apparatus .will be covered or lined with heat insulating material wherever possible so that loss of heat by radiation will be minimized.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention, which, as a matter of language might be said to fall therebetween.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. In apparatus for conditioning char and the like by heating, a vertically disposed, heated. char processing tube, a tube above said processing tube for feeding char into said processing tube, means for producing a positive pressure of air at the lower end of said processing tube, means for drawing air upwardly through said ,p'rocessing tube and downwardly through said feed tube and temperature responsive means for rendering said pressure producing and said air drawing means inoperative upon a dangerous temperature being reached within said processing tube. V

2. In apparatus for reconditioning char and the like by heating, in combination, an elongated retort divided into sections for heating at different temperatures, a boiler and a furnace for heating the same, means for passing flue gases from said furnace in series through a plurality of passes in contact with said boiler, means for extracting flue gases from a point in the final pass and conducting it directly to one section of said retort, means for extracting flue gases from a point intermediate the final pass and the furnace, means for receiving and mixing the flue gases from said points and means for passing said mixture from the mixing means into contact with a second section of said retort heated to a higher temperature than said first section.

3. In apparatus for reconditioning char and the like by heating, in combination, a retort consisting of vertically disposed process tubes adapted to receive the char to be processed, a heating chamber for heating said tubes divided into section'sfor heating at different temperatures, a

boiler and a furnace for heating the same, means for passing flue gases from said furnace in series through a plurality of passes in contact with said boiler, means for extracting flue gases from a' point in the final pass and conducting'it directlyto one section of said heating chamber, means for extracting flue gases from a point intermediate said final pass and the furnace, means for re-. ceiving and mixing the flue gases from said points and means for passing said mixture from the said second section of said heating chamber.

6. The apparatus .of claim 2 in combination with temperature actuated means for controlling the rate of flow ofsaid mixed flue gases in order to maintain the char in said second section of said'retort at a constant reconditioning tempera ture. v

7. The apparatus of claim 3 in combination with temperature actuated means for controlling the'rate of flow of said mixed flue gases to said second section of said heating chamber in the like by heating, in combination, an elongated retort divided into two sections for heating the char at different temperatures and provided with a third section for cooling the hot reconditioned char received from said heated sections, a boiler and a furnace for heating the same, means for passing flue gases from said furnace in series through a plurality of passes in contact with said boiler, means for extracting flue gases from a point in the final pass and conducting it directly to one heating section of said retort, means for extracting flue gases from a point intermediate the final pass and the furnace and for passing it into contact with the second heating section of said retort, means for passing cooling air into contact with the third section of said retort and 

